As recently as 2005-2006, a massive chikungunya (CHIK) outbreak occurred in the French Island of R[unreadable]union, infecting 35% of its 785,000 inhabitants and killing 237. Additionally, this disease is currently endemic in India, in which 1.4 to 6.5 million cases are estimated to occur in 2006-2007. The name Chikungunya comes from Swahili for "the bent walker," reflecting the physique of a person suffering from the severe joint pain associated with a chikungunya virus (CHIKV) infection. Due to the rapid and long-term debilitating effects of this disease, the US government began to study possible mechanisms to counteract this potential bioterrorist threat as early as the 1960s. To date, no vaccine has been approved for public use to prevent the deleterious effects of this dangerous mosquito-borne arbovirus. While CHIKV has remained relatively unknown among non-endemic regions of the world, its potentially devastating effects should not be ignored considering: 1) its ability to debilitate affected individuals for weeks to months after the initial infection;and 2) its recent outbreak potential, particularly in areas where there is no prior immunity. Recent and ongoing epidemics of CHIK in several islands in the Indian Ocean, and in India, have demonstrated how rapidly this arbovirus can spread through a na[unreadable]ve population and cause significant morbidity. The most effective approach to containing current and future outbreaks is to develop a safe and effective CHIK vaccine. Potential markets for this vaccine would include regions endemic for CHIKV, including multiple countries within Africa and Southeast Asia, and any potential travelers to these regions. Previously, our group has successfully developed effective recombinant vaccines against various infectious disease agents based on a CAdVax vaccine platform. These vaccines successfully protected non-human primates (NHP) from challenges by all relevant subtypes of dengue, Ebola and Marburg viruses. If we consider that symptoms of CHIKV resemble those of dengue fever and either are misdiagnosed as dengue or coincide with dengue infections, another viable market would be individuals living in or traveling to areas endemic for one of both of these debilitating arboviral infections. For this reason, we plan to develop a single-dose, multi-agent vaccine against both dengue and chikungunya viruses during our SBIR Phase II evaluations. PUBLIC HEALTH RELEVANCE: As seen last year in R[unreadable]union Island, chikungunya virus infection and outbreak is most severe when introduced into a region for which there is no prior immunity to the virus. Outbreaks of chikungunya fever can potentially incapacitate large populations of workers, leading to significant public health and economic distress. A safe and effective vaccine is the best means of preventing such naturally occurring outbreaks or potential outbreaks caused by biological attack.